Using a Cyclone Separator and a Fixed-Bed Gasifier to Generate a Product Gas from Carbon-Containing Input Substances

ABSTRACT

A cyclone separator for separating particles from a gas flow includes a gas inlet and a separating element. The separating element includes an upper cylindrical section connected to a gas outlet and a lower conical section connected to a particle outlet. The first end of the gas inlet is on a straight section, and the second end of the gas inlet in on a helical section. The second end is connected to the upper cylindrical section. The cross-sectional area of the gas inlet continually decreases, and the vertical or longitudinal dimension of the gas inlet continually increases from the first end towards the second end. The vertical dimension at the second end equals the diameter of the upper cylindrical section. A guide plate inside the straight section distributes the particles over the increasing vertical dimension of the gas inlet and prevents the particles from concentrating centrally in the gas flow.

CROSS REFERENCE TO RELATED APPLICATION

This application is filed under 35 U.S.C. § 111(a) and is based on andhereby claims priority under 35 U.S.C. § 120 and § 365(c) fromInternational Application No. PCT/EP2016/060356, filed on May 9, 2016,and published as WO 2016/180791 A1 on Nov. 17, 2016, which in turnclaims priority from German Application No. 102015208923.1, filed inGermany on May 13, 2015. This application is a continuation-in-part ofInternational Application No. PCT/EP2016/060356, which is a continuationof German Application No. 102015208923.1. International Application No.PCT/EP2016/060356 is pending as of the filing date of this application,and the United States is an elected state in International ApplicationNo. PCT/EP2016/060356. This application claims the benefit under 35U.S.C. § 119 from German Application No. 102015208923.1. The disclosureof each of the foregoing documents is incorporated herein by reference.

TECHNICAL FIELD

The invention relates to a cyclone separator and a fixed-bed gasifierfor generating a product gas from carbon-containing input substances,such a cyclone separator being downstream of the product gas outlet ofthe fixed-bed gasifier.

BACKGROUND

Fixed-bed gasifiers that generate a combustible product gas from biomasspellets, such as wood chips or wood pellets, are characterized by acomparatively simple design. A distinction exists between countercurrentgasifiers and downdraft gasifiers. In a countercurrent gasifier, thecombustion air and the product gas flow in a direction opposed to thefeed-in direction of the biomass particles. In a downdraft gasifier,however, the feed-in direction of the biomass particles matches the flowdirection of combustion air and product gas. Fixed-bed gasifiers havedifferent reaction zones, such as a drying zone, a pyrolysis zone, anoxidation zone and a reduction zone, in which different thermochemicalreactions take place.

An overview on the subject of fixed bed gasification of biomassparticles was disclosed by Lettner, Haselbacher and Timmerer from theTechnical University of Graz, Austria, in the presentation entitled“Festbett-Vergasung-Stand der Technik (Überblick)” (an overview of thestate of the art of fixed bed gasification) given on Feb. 27, 2007 atthe conference in Leipzig entitled “Thermo-chemische Biomasse-Vergasungfür eine effiziente Strom/Kraftstoffbereitstellung-Erkenntnisstand 2007”(thermo-chemical biomass gasification for efficient current/fuelsupply—state of the art in 2007). The presentation describes a downdraftshaft gasifier in which the biomass particles are supplied into thegasifier container from above using gravity. In the middle area of thegasifier, combustion air is supplied via nozzles and the product gas isdischarged from the lower area of the gasifier container. A drying zone,a pyrolysis zone, an oxidation zone and a reduction zone are arrangedfrom top to bottom in this known fixed-bed gasifier. The oxidation zoneis located within the area of the air supply and is to be restricted tothat zone. The reduction zone is beneath the oxidation zone and isdirectly above the grate. The product gas is removed from the area ofthe gasifier container beneath the grate, through which small particlesof ash fall and are collected.

The process of fixed bed gasification causes the product gas to containsolid particles of different sizes. The largest solid particlestypically are separated using a downstream cyclone separator. One suchcyclone separator is disclosed by German patent DE 4233174 A1. Thatcyclone separator has a downwardly tapered separating element with alongitudinal axis, a gas outlet reaching into the separating elementfrom above, a particle outlet located on the lower end of the separatingelement, and a gas inlet leading into the separating elementtransversely to the longitudinal axis of the separating element. The gasinlet has a first end and a second end; the second end leads into theseparating element. The gas inlet widens in an axial direction of theseparating element and helically surrounds the separating element. Thecross-sectional area of the gas inlet remains substantially constantbetween the first end and the second end of the gas inlet. A similarcyclone separator is disclosed by German patent DE 825332 B, in whichthe cross-sectional area between the first and second ends of the gasinlet increases. The particle-separating efficiency of these knowncyclone separators is insufficient, particularly when being used forpurifying product gas from fixed-bed gasifiers.

It is an object of the present invention to provide a cyclone separatorthat exhibits separation properties superior to those of the cycloneseparators disclosed in DE 4233174 A1 and DE 825332 B. Moreover, it isan object of the invention to provide a fixed-bed gasifier forgenerating a product gas from carbon-containing input substances usingthe improved cyclone separator.

SUMMARY

The invention specifies a cyclone separator with improved separatingproperties and also a fixed-bed gasifier for generating a product gasfrom carbon-containing input substances using such a cyclone separator.The gas inlet widens helically in the flow direction. The helicalwidening of the gas inlet improves the particle-separating efficiency.The widening of the gas inlet assists the forming and maintaining of thevortex flow in the separating element. The reduction in cross-sectionalarea of the gas inlet increases the flow speed and therefore theefficiency of the particle separation.

The cyclone separator for separating solid particles from a gas flowincludes a gas inlet, a separating element, a particle outlet and a gasoutlet. In one embodiment, the solid particles are ash produced in adowndraft fixed-bed gasifier during the gasification of biomassparticles into wood gas. The separating element includes an uppercylindrical section and a lower conical section. The gas outlet isconnected to the upper cylindrical section, and the particle outlet isconnected to the lower conical section. The gas inlet has a first end, asecond end, a straight section and a helical section. The first end ison the straight section, and the second end is on the helical section.The helical section is connected at the second end to the uppercylindrical section of the separating element. The straight section isoriented perpendicular to the longitudinal axis of the separatingelement.

The cross-sectional area of the gas inlet continually decreases from thefirst end towards the second end such that the cross-sectional area atthe second end is smaller than the cross-sectional area at the firstend. The longitudinal or vertical dimension of the gas inlet is orientedparallel to the longitudinal axis of the separating element. Thelongitudinal dimension of the gas inlet does not decrease from the firstend towards the second end. In one embodiment, the longitudinaldimension of the gas inlet continually increases from the first endtowards the second end. The longitudinal dimension of the gas inlet atthe second end approximately equals the diameter of the uppercylindrical section. A guide plate is disposed inside the straightsection of the gas inlet and runs midway between the upper edge and thelower edge of the straight section. The guide plate distributes thesolid particles over the widening longitudinal dimension of the gasinlet and prevents the particles from being concentrated centrally inthe gas flow.

In another embodiment, the separating element has a second conicalsection disposed between the upper cylindrical section and the lowerconical section. Adding the second conical section causes thecross-sectional area of the separating element to expand in a jump afterfirst decreasing in a downwardly direction. In yet another embodiment,the cyclone separator has a second separating element. The gas inlet hasa second helical section that is connected to the second separatingelement. The straight section of the gas inlet is connected to both thefirst helical section and the second helical section.

In yet another embodiment, a fixed-bed gasifier for producing a productgas from biomass particles includes a cyclone separator. The fixed-bedgasifier also includes a gasifier container, a gasifier component, abiomass supply inlet, an air supply inlet, a grate and a product gasvent. The diameter of the gasifier container is larger than the diameterof the gasifier component. The lower open end of the gasifier componentextends down into the gasifier container. The supply inlet is adapted toreceive the biomass particles into the upper closed end of the gasifiercomponent. Combustion air enters the gasifier component through the airsupply inlet near the upper closed end. The grate is adapted to supportthe biomass particles and is disposed in a lower portion of the gasifiercontainer. The product gas vent leads out of the gasifier containerbelow the grate. The product gas generated from the biomass particlesexits the gasifier container through the product gas vent.

The cyclone separator has a separating element and a gas inlet. The gasinlet has a first end, a second end, a straight section and a helicalsection. The first end is on the straight section, and the second end ison the helical section. The product gas enters the cyclone separatorfrom the product gas vent at the first end of the gas inlet. The helicalsection is connected at the second end to the separating element. Thegas inlet has a cross-sectional area that continually decreases from thefirst end towards the second end. The gas inlet has a vertical dimensionor length that does not decrease from the first end towards the secondend. In one embodiment, the vertical dimension of the gas inletcontinually increases from the first end towards the second end.

Other embodiments and advantages are described in the detaileddescription below. This summary does not purport to define theinvention. The invention is defined by the claims.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawings, where like numerals indicate like components,illustrate embodiments of the invention.

FIG. 1 is a schematic cross-sectional view of an exemplary embodiment ofthe cyclone separator of the present invention.

FIG. 2 is a schematic cross-sectional view of the exemplary embodimentof FIG. 1 with the section plane being perpendicular to the sectionplane of FIG. 1.

FIG. 3 is a schematic perspective view of the embodiment of FIGS. 1 and2 from the side.

FIG. 4 shows an alternative embodiment of the cyclone separator havingtwo jumps in the cross-sectional area directly before the lock device.

FIG. 5 shows an additional embodiment of the cyclone separator as adouble cyclone.

FIG. 6 is a schematic cross-sectional view of an exemplary embodiment ofa fixed-bed gasifier that includes a temperature measurement device anda rotary grate.

DETAILED DESCRIPTION

Reference will now be made in detail to some embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings.

FIG. 1 is a cross-sectional top view of an embodiment of the cycloneseparator 10 of the present invention. FIG. 2 is a side view of thecyclone separator 10 of FIG. 1. The particle-separating efficiency ofthe cyclone separator 10 is improved by the helical widening of the gasinlet 11. The widening of the gas inlet 11 allows the vortex flow in theseparating element 12 to be formed and maintained. The reduction in thecross sectional area of the gas inlet 11 increases the flow speed andtherefore the efficiency of the particle separation.

Practical experience shows that particle separation is improved bymaking the minimum cross-sectional area of the helical portion 13 of thecyclone separator 10 between 40% to 60% of the initial cross-sectionalarea of the inlet to the helical portion. Particle separation is alsoimproved by extending the gas inlet 11 in the axial direction of theseparating element 12 by a length corresponding to the largest diameterof the separating element 12. Particle separation is also improved bycontinuously reducing the cross-sectional area of the gas inlet 11.Homogenous particle distribution is achieved in the straight section 14of the gas inlet 11. In addition, the straight section 14 also assistswith the agglomeration that yields larger particles, which are easier toseparate.

Solid particles are distributed over the entire cross-section of the gasinlet 11 by using a guide plate 15 disposed in the expandingcross-section of the gas inlet 11. The cross-sectional expansion of theseparating element 12 in jumps results in changes of the speed of thegas flow, which leads to an increased agglomeration of smaller particlesinto larger particles. This improves the particle separation rate.Improved agglomeration is possible in particular with “sticky”particles, such as coke particles.

An embodiment of the cyclone separator in form of a double cyclonelikewise increases the particle separation rate. The particle separationrate decreases in higher gas flows and larger separating elements. Theconfiguration as a double cyclone compensates for the negative effectsof higher gas flows and larger separating elements.

An embodiment of a downdraft, fixed-bed gasifier 16 allows for safe andstable process control and provides a continuous flow of product gaswith low tar quantities. The product gas is typically wood gas or a gasmixture containing hydrogen gas, carbon monoxide and methane. Air issupplied through a cylindrical gasifier component 17 and into the bed ofbiomass particles, which results in a uniform distribution of the air.Hardly any temperature differences occur in the oxidation zone 18 of thegasifier container 19 by virtue of the uniform distribution. As aresult, even pyrolysis gases generated over the oxidation zone 18 flowthrough the oxidation zone in a uniform manner. The uniformity of thegas and air flows allows the product gas to be generated with low tarquantities. For additional details on such a configuration of thefixed-bed gasifier 16, see U.S. Patent Application Publication2017/0275543, which claims priority to German applicationDE102014225166.4, the subject matter of which is incorporated herein byreference.

FIGS. 1-3 show the exemplary configuration of cyclone separator 10 inaccordance with the present invention. Cyclone separator 10 has adownwardly tapered separating element 12 that ends in a particle outletin the form of a lock device 20 used to remove the separated solidparticles. The separating element 12 includes an upper cylindricalsection 21 and a lower conical section 22. The cylindrical section 21has a constant circular cross-section. Beneath the cylindrical section21 is the conical section 22 that ends with the lock device 20. Atubular gas outlet 23 projects from the cylindrical section 21 on theupper end of the separating element 12. Purified gas with a reducedproportion of solid particles is supplied through the gas outlet 23. Thetubular gas outlet 23 extends down into separating element 12 and endsbefore the conical section 22.

The gas containing solid particles, i.e., the product gas from thefixed-bed gasifier 16, is supplied to separating element 12 through thegas inlet 11 that extends transversely to the longitudinal axis ofseparating element 12. The gas inlet 11 has a first end 24, a second end25, the straight section 14 and the helical section 13. The helicalsection 13 of the gas inlet 11 wraps around a portion of the uppercylindrical section 21 of the separating element 12. The gas containingsolid particles enters at the first end 24 of the gas inlet 11 andsuccessively flows through the straight section 14 and then through thehelical section 13 and finally enters the cylindrical section 21 of theseparating element 12 through the second end 25 of the gas inlet 11. Thefirst end 24 of gas inlet 11 has a rectangular cross-section with afirst cross-sectional area 26. The gas inlet 11 widens between the firstend 24 and the second end 25 so that the largest longitudinal dimension28 of gas inlet 11 at the second end 25 approximately corresponds to thediameter 29 of the cylindrical section 21 of separating element 12. Thelongitudinal dimension of gas inlet 11 is oriented vertically andparallel to the longitudinal axis of separating element 12. While thelongitudinal dimension of gas inlet 11 is increasing towards the secondend 25, the cross-sectional area of gas inlet 11 is continuallydecreasing to a minimum cross-sectional area 27 at the second end 25 ofgas inlet 11. The ratio of the areas 27 to 26 in the exemplaryembodiment is 0.5. The cross-sectional area 26 at the first end 24should be at least twice a large as the cross-sectional area 27 at thesecond end 25 of gas inlet 11. By increasing the longitudinal dimensionof the gas inlet 11 towards the second end 25, the cross-sectional area27 is elongated at the second end 25, which leads into the cylindricalsection 21 of separating element 12 in an elongated manner and with thesmaller cross-sectional area 27. In one embodiment, the longitudinaldimension of the gas inlet 11 continually increases from the first end24 towards the second end 25. In another embodiment, such as the onedepicted in FIG. 2, the longitudinal dimension of the gas inlet 11 doesnot decrease at any point in the direction from the first end 24 towardsthe second end 25; there is, however, a portion of the gas inlet 11 overwhich the longitudinal dimension does not increase.

In the straight section 14 of gas inlet 11, the straight guide plate 15is oriented in the flow direction, which distributes the solid particlesover the widening cross-section of the gas inlet and prevents theparticles from being concentrated centrally in the gas flow. The gasinlet 11 has an upper edge 30 and a lower edge 31. The upper edge 30 isperpendicular to the longitudinal axis of the separating element 12. Thelower edge 31 forms an obtuse angle with the longitudinal axis and anacute angle with the horizontal axis. The guide plate 15 runs midwaybetween the upper edge 30 and the lower edge 31.

FIG. 4 shows an alternative embodiment of cyclone separator 10 thatincludes a separating element 12. The cyclone separator has twoexpansions or jumps 32 in the cross-sectional area of the separatingelement 12 in the flow direction above the lock device 20. In theembodiment of FIG. 4, the jumps 32 are achieved by adding a secondconical section 33 between the upper cylindrical section 21 and thelower conical section 22. The jumps 32 in the cross-sectional area causea change in the speed of the gas flow and thereby increase theagglomeration of smaller particles into larger ones. As larger particlesare easier to separate, the particle separation rate increases.

FIG. 5 shows an additional embodiment of cyclone separator 10 in theform of a double cyclone with a common straight section 14 leading intoa first helical section 13 and a second helical section 34 rotating inopposite directions. The helical sections 13 and 34 then lead into firstand second separating elements 12 and 35.

FIG. 6 is a schematic view of an exemplary configuration of a fixed-bedgasifier 16 in accordance with the present invention. The fixed-bedgasifier 16 includes a cylindrical gasifier container 19, the ends ofwhich are closed by an upper cover 36 and a lower cover 37. Thecylindrical gasifier component 17 has a lower, open end 38 and an upper,closed end 39. The gasifier component 17 projects down into the gasifiercontainer 19 with the open end 38. The closed end 39 of the gasifiercomponent 17 protrudes out from the gasifier container 19 through theupper cover 36. The lower, open end 38 of gasifier component 17 liesapproximately at the middle of gasifier container 19. A rotary grate 40is disposed at a distance 41 below the open end 38 of the gasifiercomponent 17. The rotary grate 40 can be periodically rotated by therotational shaft 42 of a motor drive 43 that penetrates up through thelower cover 37. The upper, closed end 39 of gasifier component 17 ispenetrated by a supply inlet 44 for carbon-containing input substancessuch as pourable biomass particles 45, an air supply inlet 46 throughwhich combustion air 47 enters the gasifier container 19, and a levelsensor 48 by which the level of biomass particles 45 in the cylindricalgasifier component 17 is determined and monitored. The upper, closed end39 of gasifier component 17 projects up and out of gasifier container19. An inspection shaft 49 penetrates the outer wall of gasifiercontainer 19 at the level of the open end 38 of gasifier component 17.The inspection shaft 49 is closed by a covering flange 50 that is partof a temperature measurement device 51. The temperature in the gasifiercontainer 19 is monitored using the temperature measurement device 51.Access into the reactor vessel can be gained through the inspectionshaft 49 in order to perform maintenance and cleaning work inside thereactor vessel during the standstill of the reactor.

The rotary grate 40 includes a disk-shaped main part that supports thecarbon-containing input substances, such as the biomass particles 45.The main part of the rotary grate 40 is mounted centrally onto therotational shaft 42 that penetrates the lower cover 37 of gasifiercontainer 19 and is rotated by motor drive 43. A dome-shaped covering 52is located on the upper side of the rotary grate 40 in the centralregion above the rotational shaft 42. A plurality of slit-shapedopenings 53 are made in concentric circles around the center of therotary grate 40 and allow ash and product gas to pass through the rotarygrate 40.

The product gas is removed from the region of the gasifier container 19beneath grate 40 through a product gas vent 54. The product gas is thencooled in heat exchanger 55 and purified in a downstream cycloneseparator 10. The ashes falling through the grate 40 are also dischargedfrom the fixed-bed gasifier 16 through the product gas flow via theproduct gas vent 54.

Both the cylindrical gasifier container 19 and the cylindrical gasifiercomponent 17 have a circular cross-section and are arrangedconcentrically to one another. The cylindrical gasifier component 17 hasan inner diameter 56 that is smaller than the inner diameter 57 of thecylindrical gasifier container 19.

REFERENCE NUMERALS

-   10 cyclone separator-   11 gas inlet of cyclone separator-   12 separating element-   13 helical section of gas inlet-   14 straight section of gas inlet-   15 guide plate-   16 downdraft, fixed-bed gasifier-   17 gasifier component-   18 oxidation zone-   19 gasifier container-   20 lock device of cyclone separator-   21 upper cylindrical section-   22 lower conical section-   23 gas outlet of cyclone separator-   24 first end of gas inlet-   25 second end of gas inlet-   26 cross-sectional area of first end-   27 cross-sectional area of second end-   28 largest longitudinal dimension of gas inlet-   29 diameter of cylindrical section-   30 upper edge of straight section of gas inlet-   31 lower edge of straight section of gas inlet-   32 jumps in area of separating element-   33 second conical section of separating element-   34 second helical section of gas inlet-   35 second separating element-   36 upper cover-   37 lower cover-   38 lower open end of gasifier component-   39 upper closed end of gasifier component-   40 rotary grate-   41 distance from gasifier component to grate-   42 rotational shaft of motor drive-   43 motor drive-   44 supply inlet for carbon substances-   45 biomass particles-   46 air supply inlet-   47 combustion air-   48 level sensor-   49 inspection shaft-   50 covering flange-   51 temperature measurement device-   52 dome-shaped covering-   53 slit-shaped openings in grate-   54 product gas vent-   55 heat exchanger-   56 inner diameter of gasifier component-   57 inner diameter of gasifier container

Although the present invention has been described in connection withcertain specific embodiments for instructional purposes, the presentinvention is not limited thereto. Accordingly, various modifications,adaptations, and combinations of various features of the describedembodiments can be practiced without departing from the scope of theinvention as set forth in the claims.

1-13. (canceled)
 14. A cyclone separator for separating solid particlesfrom a gas flow, comprising: a separating element with a longitudinalaxis, wherein the separating element includes an upper cylindricalsection and a lower conical section; a gas outlet connected to the uppercylindrical section; a particle outlet connected to the lower conicalsection; and a gas inlet that has a first end, a second end, a straightsection and a helical section, wherein the first end is on the straightsection and the second end is on the helical section, wherein thehelical section is connected at the second end to the upper cylindricalsection of the separating element, wherein the straight section isoriented perpendicular to the longitudinal axis of the separatingelement, wherein the gas inlet has a cross-sectional area at the secondend that is smaller than the cross-sectional area at the first end,wherein the cross-sectional area of the gas inlet continually decreasesfrom the first end towards the second end, wherein the gas inlet has alongitudinal dimension oriented parallel to the longitudinal axis of theseparating element, and wherein the longitudinal dimension of the gasinlet does not decrease from the first end towards the second end. 15.The cyclone separator of claim 14, wherein the longitudinal dimension ofthe gas inlet continually increases from the first end towards thesecond end.
 16. The cyclone separator of claim 14, wherein thecross-sectional area at the first end of the gas inlet is at least twicea large as the cross-sectional area at the second end.
 17. The cycloneseparator of claim 14, wherein the cross-sectional area at the secondend of the gas inlet is 60% or smaller than the cross-sectional area atthe second end.
 18. The cyclone separator of claim 14, wherein the uppercylindrical section of the separating element has a diameter, andwherein the longitudinal dimension of the gas inlet at the second endapproximately equals the diameter of the upper cylindrical section. 19.The cyclone separator of claim 14, wherein the gas outlet is tubular andprotrudes down into the upper cylindrical section from above.
 20. Thecyclone separator of claim 14, wherein the helical section of the gasinlet wraps around a portion of the upper cylindrical section of theseparating element.
 21. The cyclone separator of claim 14, wherein thesolid particles are ash produced by the gasification of biomassparticles into wood gas.
 22. The cyclone separator of claim 14, whereinthe straight section of the gas inlet has an upper edge and a loweredge, and wherein the upper edge is oriented perpendicular to thelongitudinal axis of the separating element.
 23. The cyclone separatorof claim 22, wherein a guide plate is disposed inside the straightsection of the gas inlet, and wherein the guide plate runs midwaybetween the upper edge and the lower edge.
 24. The cyclone separator ofclaim 14, wherein the separating element has a second conical sectiondisposed between the upper cylindrical section and the lower conicalsection.
 25. The cyclone separator of claim 14, wherein thecross-sectional area of the separating element expands in a jump afterdecreasing in a downwardly direction.
 26. The cyclone separator of claim14, further comprising: a second separating element, wherein the gasinlet has a second helical section that is connected to the secondseparating element, and wherein the straight section of the gas inlet isconnected to both the helical section and the second helical section.27. A fixed-bed gasifier for producing a product gas from biomassparticles, comprising: a gasifier container with a first diameter; agasifier component with a second diameter, an upper closed end and alower open end, wherein the lower open end of the gasifier componentextends down into the gasifier container, and wherein the first diameteris larger than the second diameter; a supply inlet adapted to receivethe biomass particles into the upper closed end of the gasifiercomponent; an air supply inlet that enters the gasifier component nearthe upper closed end and through which combustion air enters thegasifier component; a grate adapted to support the biomass particlesthat is disposed in a lower portion of the gasifier container; a productgas vent leading out of the gasifier container below the grate andthrough which the product gas generated from the biomass particles exitsthe gasifier container; and a cyclone separator having a separatingelement and a gas inlet, wherein the gas inlet that has a first end, asecond end, a straight section and a helical section, wherein the firstend is on the straight section and the second end is on the helicalsection, wherein the product gas enters the cyclone separator from theproduct gas vent at the first end of the gas inlet, wherein the helicalsection is connected at the second end to the separating element, andwherein the gas inlet has a cross-sectional area that continuallydecreases from the first end towards the second end.
 28. The fixed-bedgasifier of claim 27, wherein the gas inlet has a vertical dimensionthat does not decrease from the first end towards the second end. 29.The fixed-bed gasifier of claim 27, wherein the gasifier component isarranged coaxially with respect to the gasifier container.
 30. Thefixed-bed gasifier of claim 27, wherein the grate is rotatable.
 31. Thefixed-bed gasifier of claim 27, wherein the cyclone separator is adaptedto separate ash from the product gas which are produced by thegasification of the biomass particles.
 32. The fixed-bed gasifier ofclaim 27, wherein a heat exchanger is disposed between the product gasvent and the gas inlet of the cyclone separator.